Title: Port of the week: pup

	Title: Port of the week: pup
	Author: Solène
	Date: 22 April 2021
	Tags: internet
	Description:

	# Introduction

	Today I will introduce you to the utility "pup" providing CSS selectors
	filtering for HTML documents. It is a perfect companion to curl to
	properly fetch only a specific data from an HTML page.

	On OpenBSD you can install it with `pkg_add pup` and check its
	documentation at /usr/local/share/doc/pup/README.md

	pup official project

	# Examples

	pup is quite easy to use once you understand the filters. Let's see a
	few examples to illustrate practical uses.

	## Fetch my blog titles list to a JSON format

	The following command will returns a JSON structure with an array of
	data from the tags matching "a" tags with in "h4" tags.

	```command line example
	curl https://dataswamp.org/~solene/index.html \| pup "h4 a json{}"
	```

	The output (only an extract here) looks like this:

	```output truncated
	[
	{
	"href": "2021-04-18-ipfs-bandwidth-mgmt.html",
	"tag": "a",
	"text": "Bandwidth management in go-IPFS"
	},
	{
	"href": "2021-04-17-ipfs-openbsd.html",
	"tag": "a",
	"text": "Introduction to IPFS"
	},
	[truncated]
	{
	"href": "2016-05-02-3.html",
	"tag": "a",
	"text": "How to add a route through a specific interface on FreeBSD 10"
	}
	]
	```

	## Fetch OpenBSD -current specific changes

	The page https://www.openbsd.org/faq/current.html contains specific
	instructions that are required for people using OpenBSD -current and
	you may want to be notified for changes. Using pup it's easy to make a
	script to compare your last data to see what has been appended.

	```command line
	curl https://www.openbsd.org/faq/current.html \| pup "h3 json{}"
	```

	Output sample as JSON, perfect for further processing with a scripting
	language.

	```JSON output sample
	[
	{
	"id": "r20201107",
	"tag": "h3",
	"text": "2020/11/07 - iked.conf \u0026#34;to dynamic\u0026#34;"
	},
	{
	"id": "r20210312",
	"tag": "h3",
	"text": "2021/03/12 - IPv6 privacy addresses renamed to temporary addresses"
	},
	{
	"id": "r20210329",
	"tag": "h3",
	"text": "2021/03/29 - [packages] yubiserve replaced with yubikeyedup"
	}
	]
	```

	I provide a RSS feed for that

	# Conclusion

	There are many possibilities with pup and I won't list them all. I
	highly recommend reading the README.md file from the project because
	it's its documentation and explains the syntax for filtering.